Fluorescence sensors for Zn2+ based on conjugated indole Schiff base

Two novel fluorescence probes based on conjugated Schiff base for the detection of Zn 2+ were developed. Corresponding molecular geometries, orbital energies, electron contributions and absorption properties of the fluorescence probes were calculated at B3LYP/6-31G ∗ by density functional theory. The fluorescence properties of the probes were investigated by UV–vis and fluorescence spectrometer. Results indicate that the probes exhibit excellent sensitivity and selectivity for Zn 2+ compared with metal ions examined. For example, the enhancement efficiency of the compound 2 for Zn 2+ is up to 846%. The detection limit of the sensor toward Zn 2+ could low to 1.0   ×   10 −7   M. Moreover, mechanisms for the high selectivity and sensitivity of the probes to Zn 2+ were studied.